Niemann-Pick disease type C is a very rare inherited inability to metabolize cholesterol and other fats. Because of this inability, cholesterol accumulates in the liver and the spleen and other fats accumulate in the brain, causing progressive neurodegeneration. In most cases, neurological symptoms appear between the ages of 4 and 10 years, but the disease may not appear until a person is an adult. Progression is slower the later the symptoms appear, but Niemann-Pick C is always fatal. The majority of children with the disease die before the age of 20. No treatment is known. The researchers are developing a therapy for children with Niemann-Pick C based on a neurosteroid, a hormone that acts on the growth and differentiation of brain cells and is produced in the nervous tissue. The drug has shown activity in both increasing brain cell survival and reducing the accumulation of fats in the brain that causes the brain degeneration. The collaboration includes the completion of the following studies on ALLO: - Formulation development - Pharmacokinetic/absorption, distribution, metabolism, and excretion (PK/ADME) studies - Investigational New Drug (IND)-directed toxicology